Ordering logical units in a subgroup of a consistency group

1. A processing system for ordering logical units in a subgroup of a consistency group, the processing system comprising: a processor in communication with a storage device and a network adapter, the processing system configured to perform a method comprising: defining a primary storage consistency group in a primary storage comprising one or more subgroups that each comprise a first grouping of logical units; defining a secondary storage consistency group in a secondary storage comprising one or more subgroups that each comprise a second grouping of logical units, updates to the primary storage consistency group are copied to the secondary storage consistency group in the same order they were made to the primary storage consistency group; copying, by a computer processor, the primary storage consistency group to the corresponding secondary storage consistency group; monitoring one or more usage characteristics of each of the first grouping of logical units in the primary storage consistency group; assigning a priority to each of the first grouping of logical units in the primary storage consistency group; detecting an abnormal condition in a process for copying the primary storage consistency group from the primary storage to the secondary storage consistency group in the secondary storage, wherein the abnormal condition is a reduction in an available bandwidth between the primary storage and the secondary storage that prevents the primary storage consistency group from being copied in a timely manner to the secondary storage consistency group; and based on detecting of the abnormal condition, removing one or more of the first grouping of logical units in the primary storage consistency group from the process for copying the primary storage consistency group from the primary storage to the secondary storage consistency group in the secondary storage, wherein the one or more of the first grouping of logical units to be removed is based on the priority assigned to the one or more of the first grouping of logical units.

2. The processing system of claim 1 , wherein the priority assigned to each of the first grouping of logical units in the primary storage consistency group is based on the one or more usage characteristics of each of the first grouping of logical units in the primary storage consistency group.

3. The processing system of claim 2 , wherein the one or more usage characteristics of each of the first grouping of logical units in the primary storage consistency group comprise a frequency of writes to each of the first grouping of logical units in the primary storage consistency group.

4. The processing system of claim 3 , wherein the priority assigned to each of the first grouping of logical units in the primary storage consistency group is positively correlated with the frequency of writes to each of the first grouping of logical units in the primary storage consistency group.